I think the premise was totally reasonable because of the probabilities involved. Instead of a single hack resulting in a smoking crater, I think it's far more

I think the premise was totally reasonable because of the probabilities involved. Instead of a single hack resulting in a smoking crater, I think it's far more likely that the enemy will quietly amass a large library of exploits over a period of years, and then unleash them all at once to impede emergency service response, leverage panic, comm failures. This also means that instead of a 100pct success on one essential target like a nuclear plant, the enemy can work with thousands of 10pct successes against softer targets like EMS, power, transport, economy, etc.